Review on Xylella fastidiosa: reference to a possible presence in Europe on grapevine
Xylella fastidiosa (EPPO A1 quarantine pest) infects many plant species, mostly woody perennials. In a recent paper, Purcell (1997) has established a list of these diseases (see below), for some of them the implication of X. fastidiosa has still to be confirmed. It can also be noted that a disease caused by X. fastidiosa on coffee has been recently found in Brazil (EPPO RS 96/169). Although the strains of X. fastidiosa are grouped as a single species, they differ in host range, pathogenicity, nutritional fastidiousness and DNA homology. It is felt that X. fastidiosa probably consists of more than one pathovar or subspecies (Purcell ; Hopkins, 1996).
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Plant diseases
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Reported occurrence
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Grapevine Pierce’s disease
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Costa Rica, Mexico, Peru, USA (southern)
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Alfalfa dwarf
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USA (California)
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Almond leaf scorch
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Argentina, India (doubtful), USA (California)
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Peach phony
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USA (south-eastern)
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Plum leaf scald
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Brazil, Paraguay, USA (south-eastern)
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Maple leaf scald
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USA (eastern)
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Oak leaf scorch
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USA (eastern)
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Elm leaf scorch
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USA (eastern)
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Sycamore leaf scorch
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USA (eastern)
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Mulberry leaf scorch
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USA (eastern)
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Periwinkle wilt
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USA (Florida)
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Ragweed stunt
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USA (Florida)
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Citrus variegated chlorosis
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Argentina (symptoms observed), Brazil
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Pear leaf scorch (unconfirmed)
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Taiwan
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Oleander leaf scorch
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USA (California)
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Stunting diseases of nutgrass, poison hemlock, blackberry, Dallis grass
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USA (California)
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(from Purcell, 1997)
From a quarantine point of view, the author felt that due to the broad host range of this bacterium, and the fact that new strains probably remain to be recognized or discovered (as shown by the recent findings of X. fastidiosa on oleander (EPPO RS 97/049) and coffee), phytosanitary measures should prevent the introduction of the bacterium by monitoring the movement of live plants from regions where X. fastidiosa occurs
The possible presence of X. fastidiosa in Europe is mentioned by Purcell, and is based on an abstract published in Phytopathology (Berisha et al., 1996). In this abstract, it is said that X. fastidiosa, the causal agent of Pierce’s disease, has been isolated from diseased grapevines grown in Kosovo (Yugoslavia). The EPPO Secretariat wrote to the authors of this abstract to try to obtain more information on this record. Unfortunately, it was not possible for them to provide more details on the origin of the affected plants, the possible extent of the disease in Kosovo vineyards, the origin of the disease, etc. This issue will have to be followed closely but the report must for the moment be regarded as ‘unconfirmed’.
Sources
Purcell, A.H.; Hopkins, D.L. (1996) Fastidious xylem-limited bacterial plant pathogens.
Annual Review of Phytopathology, 34, 131-151.
Purcell, A.H. (1997) Xylella fastidiosa, a regional problem or global threat?
Journal of Plant Pathology, 79(2), 99-105.
Berisha, B.; Chen, Y.D.; Xu, Y.; Chen, T.A. (1996) Isolation of Pierce’s disease bacteria from grapevines in Europe (abstract).
Phytopathology, 86(11) Supplement, p S119.